Rose wasn't doing very well herself. Well it was nice that she wasn't stuck, and that no one else was stuck. But even since they had been freed of their captors, it still felt like a prison. And it still felt like she was all by herself. By herself while one Doctor fooled around with Jack, and the other one seemed to be fooling around with the Master.
Weird.
So she stuck to being by herself. It wasn't like she had anyone else. Still she was happy to go with a new Doctor and find some tea. It would help to get out and walk around not by herself. When the door knocked, she went to open it up.